Preparation of barium dicyanimide



TATES PATENT OFFICE PREPARATION OF BARIUM DICY s Daniel E. Nagy and Bryan C. Redmon, Stamford,

Conn, assignors to American Cyanamid Company, New York, N. Y., a corporation of Maine No Drawing. Application September 22, 1945, Serial No. 618,072

2 Claims. (01. 23-75) 1 2 This invention relates to barium dicyanimide to a, the elongated crystal axis. It is to be und its p paration. derstood that the symbols a, b, and 0, refer to The present invention contemplates that barithe crystallographic axes. um dicyanimide may be prepared by the reaction Although the above example describes the of barium hydroxide with a metal salt of dicy- 5 preparation of barium dicyanimide from zinc dianimide, the metal proportion of which forms an cyanimide, it may also be prepared in a similar hydroxide whose solubility is less than the aforemanner by precipitating calcium and/or copper mentioned metal dicyanimide. The general rehydroxide from the corresponding dicyanimide action for the formation of barium dicyanimide salt. The insoluble hydroxides are removed prior is given in Equation 1. to the recovery of barium dicyanimide from (1) /CN 0N aqueous solution. 1

Barium dicyanimide is a valuab e chemical in- 2M1\\ Baum)? Ba N 2MOH termediate and a source of dicyanimide which ON ON 2 is useful in the preparation of pharmaceuticals, Where M i met l which gives an hydroxid 16 chemotherapeutic agents, insecticides, seed dismore insoluble than its dicyanimide San, The a t plastics. resins, e t a e ts, and t e preferred metal salts of dicyanimide which unlike Barium dicyanimide y b used D e s dergo the reaction of the present invention are an insecticidethe calcium, copper, and zinc dicyanimid s The While the invention has been described with example which follows is typical of the m thod 20 particular reference to specific embodiments, it of preparing barium dicya imid is to be understood that it is not to be limited thereto but is to be construed broadly and re- Emmple stricted solely by the scope of the appended claims.

Approximately 2 mols of wet zinc dicyanimide is suspended in 500 ml. of water, and this suspension is made alkaline to phenolphthalein by the careful addition of approximately 1.5 mols of barium hydroxide solution. This reaction mixmlde Salt of metal chosen from the group ture is thoroughly agitated and the tempera sisting of calcium, copper, and zinc with barium ture is kept below substantially C. Aft hydrox1de to produce a substantially insoluble about an hour the resultant zinc hydroxide is hydroxide and barium dicyammlde, and remov- 26 What is claimed:

1. A method of preparing barium dicyanimide which includes the steps of reacting a dicyaniremoved, by filtr ti Th filtrate is neutralized ing the aforementioned substantially insoluble with dilute hydrochloric acid and evaporated unhydroxide 0111 the barium dicyanimideder reduced pressure. A substantially quantita- A method of Preparing b um dicyanimide tive yield of colorless crystalline barium dicywhich includes the ps of reacting an aqueous animide is obtained. This material does not melt ry containing Zine dicyanimide W t barium or decompose below substantially 315 C. and it is droxide to form substantially insoluble Zine not hygroscopic, hydroxide and soluble barium dicyanimide, re-

In order to characterize this solid, the optical moving the Substantially insoluble Z1110 hydroxide and crystallographic properties are de rib d, from the aqueous solution containing barium di- Barium dicyanimide crystallizes i th th cyanimide, concentratin the resultant solution rhombic system in a columnar habit whose form to form solid barium dicyanimid a r ve in is (001) (100) (010), and it has a positive optic t e ba um y e.

sign. The principal refractive indices as observed in white light are as follows: DANIEL E. NAGY.

BRYAN C. D oc=1.463i0.003; {3=1.616:0.003; RE MON and 'y is greater than 1.83. The apparent optic REFERENCES CITED axial angle as observed in air is 117, and the true he followin references are of record in the optic axial angle computed therefrom is 62. The file Of t s P t:

optic axial plane or principal optic section is the Chemical Abstracts, article by Franklin, vol. plane (010). The crystals are oriented so that 16 (1922), p e 1194; a so urnal Of the Amerithe principal vibration directions are as follows: can Chemical Society, vol. 44 (1922), pages 0: is parallel to c; B is parallel to b; 'y is parallel 65 486-509. 

